Optical member

Abstract

The present invention relates to an optical element and, more particularly relates to an optical element having at least one surface in which an antireflection concave-convex structure is formed. The present invention provides an optical member in which the generation of diffraction light and reflection is sufficiently suppressed and which has a structure that can be formed in a simple manner. On a first lens surface ( 10 ) of a lens 1, an antireflection concave-convex structure ( 11 ) including a plurality of cone convex portions ( 12 ) regularly arranged is formed. The antireflection concave-convex structure ( 11 ) is for suppressing reflection of light having a wavelength equal to or larger than a cycle of the cone convex portions ( 12 ). The antireflection concave-convex structure ( 11 ) is formed so that the cycle and/or a height of the structure units differ among regions of the first surface ( 10 ).

1 . An optical member having at least one surface on which an antireflection concave-convex structure which includes a plurality of structure units regularly arranged and suppresses reflection of light having a wavelength equal to or larger than a cycle of the structure units,
 wherein the antireflection concave-convex structure is formed so that the cycle and/or height of the structure units differ among regions of the surface.   
   
   
       2 . The optical member of  claim 1 , wherein the structure units are cone convex portions, cone concave portions, filiform convex portions or filiform concave portions. 
   
   
       3 . The optical member of  claim 1 , wherein an angle of the surface with respect to an optical axis differs between the regions. 
   
   
       4 . The optical member of  claim 1 , wherein the surface is a curved surface. 
   
   
       5 . The optical member of  claim 1 , wherein light coming into the optical member through the surface is output from the optical member through another surface. 
   
   
       6 . The optical member of  claim 1 , wherein the surface is formed in a concave shape or a convex shape and the antireflection concave-convex structure is formed on the surface so that the cycle and/or height of the structure units differ among an optical axis vicinity region of the surface and an edge region of the surface located closer to an edge of the surface. 
   
   
       7 . The optical member of  claim 1 , wherein an angle of the surface with respect to the optical axis changes in a step wise manner or continuously depending on a distance of a point of the surface from the optical axis and the antireflection concave-convex structure is formed on the surface so that the cycle and/or height of the structure units varies in a correlation with the angle between the surface and the optical axis.